In treating coronary artery disease, a variety of surgical techniques are employed to recanalize an occluded or partially occluded artery segment without requiring open heart surgery. Percutaneous transluminal angioplasty or related procedures have become commonly used in the treatment of various obstructive disorders of the human circulatory system. To date, these angioplasty and related procedures have been utilized to treat stenotic lesions of the coronary arteries, and other obstructive vascular lesions. In one technique, a catheter using an expandable balloon at its distal end is routed through the vascular system and ultimately into the coronary artery with the balloon being positioned at the stenotic lesion. Once positioned, the balloon is inflated to compress the plaque into the wall of the blood vessel, thus restoring circulation through the artery.
In general, the usual technique for performing angioplasty procedures requires the initial placement of an elongated flexible angio catheter known as a "guide catheter". The guide catheter is initially inserted into an appropriate artery, such as the femoral artery or axillary artery, and subsequently advanced transluminally to a point where the distal tip of the guide catheter is positioned within a target blood vessel, near the obstructive lesion to be treated. The guide catheters have an internal lumen sufficiently large to receive and pass balloon catheters, or other working catheters through them.
A flexible guide wire is inserted through the lumen of the guide catheter such that the distal end of the guide wire emerges out of and extends beyond the distal tip of the guide catheter. The guide wire is advanced under fluoroscopic guidance, to a point where the distal end of the wire has advanced fully through the stenotic lesion or obstruction to be treated. Thereafter, a small balloon catheter, imaging device or other device used to ameliorate coronary artery disease is inserted and advanced over the guide wire, through the lumen of the guide catheter, to a point adjacent the lesion or obstruction. At this point, the device is operated or the balloon is inflated one or more times to bring about the desired dilation of the offending lesion and/or distention of the surrounding blood vessel wall. After such treatment is completed, the balloon catheter (or other device), guide wire and guide catheter are withdrawn and removed from the patient.
Various types and sizes of guide catheters are available. Prior to the procedure, a guide catheter of appropriate type and size is preselected by the surgeon for each particular patient. However, sometimes a preselected guide catheter proves to be inadequate and it becomes necessary or desirable to exchange one guide catheter for another during the course of the angioplasty procedure. If the decision to change a guide catheter is reached prior to the insertion of the coronary guide wire, the guide catheter may simply be extracted and replaced before the guide wire is inserted without any substantial risk of complication. However, if, as often occurs, the decision to replace the guide catheter is not reached until after the guide wire has been fully inserted through the guide catheter and advanced through the stenotic lesion, an attempt to replace the guide catheter at that point is complicated by the need to maintain the previously inserted guide wire in its operative position, without accidentally pulling the guide wire back through the lesion.
Currently, interventional cardiologists must choose between large catheter systems and small catheter systems for guide catheter placement. The larger catheter systems allow more flexibility in terms of being able to place large perfusion balloons, atherectomy devices, or coronary stents. Systems using the smaller diameter catheters have several advantages, such as decreasing the risk of hemorrhaging around the groin area of the patient, decreasing patient morbidity, decreasing contrast usage, allowing quicker ambulation (potentially shortening the length of hospital stay), and reducing costs for the angioplasty procedure. There is hesitancy among some cardiologists, however, to use smaller guide catheter systems because of the difficulty in having to exchange to a large catheter system if it is necessary to do so during the surgical procedure.